Exhaust structure



y 0, 1966 R. L. STROUTH 3,250,206

EXHAUST STRUCTURE Filed Sept. 3, 1963 2 Sheets-Sheet l INVENTOR.

ROBERT L. STROUTH www ATTORNEYS y 0, 1966 R. L. STROUTH 3,250,206

EXHAUST STRUCTURE Filed Sept. 5, 1963 2 Sheets-Sheet 2 INVENTOR. 7g ROBERT L. STROUTH BY 73 Wwm ATTORNEYS United States Patent 3,250,206 EXHAUST STRUCTURE Robert L. Strouth, Waterloo, Ontario, Canada, assignor to The Lau Blower Company, Dayton, Ohio, a corporation of Ohio Filed Sept. 3, 1963, Ser. No. 306,118 1 Claim. '(Cl. 98-119) This invention relates to domestic exhaust systems, and particularly to ventilation hoods used with domestic exhaust fan systems and the like.

An important object of this invention is to provide an outlet ventilation hood for a ventilating system including a flutter-proof door for excluding outside air from the ventilating system, and particularly to provide a hood which eliminates springs or other biasing devices for closing the door so that variations in the biasing effect of such such fluttering.

A further object of this invention is to'provide a ventilating hood of the aforesaid type having a sealing and noise suppression device between the periphery of the shutter door and the door supporting frame to block the inward flow of air when the door is in the closed position, and particularly to provide structure of this type wherein the shutter door is shielded from the elements and is simply constructed for maximum dependability and long life while being inexpensive to manufacture.

Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.

In the drawings:

FIG. 1 is a sectional view of a ventilation-hood in accordance with the invention and mounted on the pitched roof;

FIG. 2 is an enlarged sectional view of the hood shown in FIG. 1 illustrating the operative components thereof;

FIG. 3 is a perspective view of the door and frame assembly utilized in the ventilation hood shown in FIGS. 1 and 2;

FIG. 4 is a sectional view taken essentially along the line 4-4 and showing the frame assembly mounted in the housing structure;

- FIG. 5 is a sectional view taken along the line 5-5 of FIG. 2 and showing the rear side of the door or shutter;

FIG. 6 is a sectional view of another embodiment of the invention;

FIG. 7 is a perspective view of the ventilation hood shown in FIG. 6, with the door and door shield being broken away to reveal other components of the structure; and

FIG. 8 is a front view of the ventilation hood shown in FIGS. 6 and 7.

Referring to the drawings wherein preferred embodiments of the invention are illustrated, FIG. 1 shows a ventilation hood or roof jack 10 mounted on the roof 11 of the building 12 in alignment with a square aperture 13. The roof 11 extends upwardly with a pitch angle a and the vertical exhaust duct 15 can be of any size smaller than the lower opening to the hood 10 so that the flanges 17 can be secured to the roof around the periphery of the aperture 13, and the duct 15 communicates in an airtight manner with the hood 10.

ice

The hood 10 is formed of suitable sheet metal, and includes a rectangular flange or mounting plate 17 defining an inlet opening 20 which communicates with the aperture 13 formed in the roof 11. The dome shaped cover 21 ,extends upwardly from the mounting plate and completely covers and extends beyond the opening 20, whereas the side walls 22 and 23 extend between the cover 21 and the flange 17 adjacent the sides of the opening 20. These side walls are cut from the sheet metal in the opening 20, and are subsequently bent upwards at right angles thereto and suitably secured, e.g., by resistance welding or brazing, to the cover 21.

A front wall member 25 extends upwardly from the front edge portion 26 of the flange 1 8 and includes an internal flange 27 along its upper edge. The wall 25 defines the edge of the outlet opening 30 which is bounded on its sides by the edges 32 of the Walls 22 and 23, and at the top by the forwardmost edge 35 of the cover 21. A screen 36 is preferably stretched across the outlet opening 30 and secured to flange 27 and edges 32 to prohibit the movement of undesirable rodents, insects, and the like into the building 12 through the hood 10.

An exhaust fan, not shown, is mounted within the building in communication with the duct 15, and a shutter door 40 is mounted in the hood 10 for swinging movement between an open position when the fan is in operation and a closed position when the fan is shut off. Referring particularly to FIGS. 2-3, the door 40 is supported in a U-shaped frame comprising a horizontal base section 41 and a pair of side members 42. This frame is mounted in the hood 10 by means of screws 43 which secure the side members 42 to the side Walls 22 and 23 respectively, with the base section 41 adjacent the flange position 27 of the wall 25.

The shutter door 40 is constructed of a lightweight nonmagnetic metal, such as aluminum, and has a rolled upper edge 45 for receiving the rod or axle 46 which is mounted at its opposite ends to the ears 47 projecting outwardly from the upper ends of the vertical frame members 42. The ears 47 are preferably cut from the frame members, as shown in FIG. 3, but this arrangement is subject to substantial modification within the scope of this invention. The position in which the side members 42 are secured to the side walls 22 and 23 is correlated With the pitch of the roof on which the hood 10 is to be mounted so that when the hood 10 is placed on the roof, gravity tends to hold the shutter door 40 in the closed position.

As shown in FIG. 4, a srti-p 50 of resilient sealing material is secured to the frame member 40 on the side thereof which engages the door. Particularly satisfactory results are obtained using polyurethane foam as the sealing strip 50, since this material is resilient, insensitive to normal weather condition, and will not deteriorate over long periods of use so that it provides a long lasting seal and noise suppressor between the door 40 and the frame 4142 when the door is in its closed position. Another strip 51 of this materialis placed between the upper edge 45 of'ythe door 40 and the cover 21 so that this area of the structure is also airtight.

The sealing strip 50 on the horizontal frame section 41 is cut out at 53 (FIG. 4) for accommodating the magnetic element or strip 55 which is suitably secured on the nonmagnetic door 40 and holds the same firmly in the closed position against movement until a predetermined pressure differential acts on the surface areas thereof. The thickness of the magnetic element 55 is preferably slightly less than that of the sealing strip 50 so that the latter is slightly depressed when the element 55 holds the door 40 in a closed position, thus creating an effective airtight seal around the door 40. The magnetic strip 55 is preferably a magnetized rubber material which maintains its magnetic characteristics over very long periods of time.

When the exhaust fan of the ventilation system is not operating, the magnetic element 55 holds the door 40 in the closed position, as shown in FIG. 1, thereby prohibiting the flow of air into the system through the hood 10. As mentioned above, in this closed position, the

polyurethane foam strips 50 and 51 seal between the door 40, frame 41.42 and cover 21 so that the structure is substantially airtight. The magnetic element exerts sufiicient force so that, when gusts of wind subjectthe door 40 to pressure differentials which tend to cause fluttering of the door, the door 40 is held in the closed position. However, when the exhaust fan in the building is started, it creates pressure in the duct 15 which acts on the inside of the door 40 to separate the magnetic element 55 from the frame member. Once the element 55 is separated from the frame member, the lightweight door 40 quickly opens without restriction as wide as is required by the air flow from the fan, as shown in the broken lines of FIG. 1, thus permitting the exhaust gases to be forced through the opening outwardly of the building 12.

In order to prevent any possibility of having the door 40 held in the open position by attraction between the magnet 55 and cover 21, the lower edge of the door 40 is provided with a lip 56 which can abut the wall 21 to maintain the element 55 spaced a safe distance therefrom. Then when the exhaust fan is turned off, the weight of the door 40 causes it to move to the closed position, and when it approaches this position, the magnetic element 55 is attracted to the frame 41 and moves the door quickly to the closed position wherein the duct 15 is sealed.

FIGS. 6-8 illustrate another embodiment of the invention wherein the ventilation hood is utilized in a wall cap 60, as opposed to a roof jack 10. Thus the wall cap 60 is mounted on the vertical wall 61 of a building or structure 62, and the outlet duct 63 communicates with the exhaust system in the interior of this building. The outer ends of the duct 63 are outwardly flared, as shown in FIG. 7, to form the flange 65 onto which the rectangular mounting bracket 66 is secured, for example by resistance welding. The ears 68 are cut from the mounting bracket 66 and bent perpendicularly therefrom to support the opposite ends of the rod or axle 70 which extends through the rolled edge 71 of the door 73 to support this door over the opening 75 defined by the bracket 66, the door 73 being constructed of lightweight nonmagnetic metal similarly to the door 40.

A sealing strip 77 corresponding to the seal strip 50 is secured to the bracket 66 adjacent the lower and vertical side edges of the opening 75 for sealing between the shutter door 73 and the bracket 66, in a manner described hereinbefore in connection with the embodiment shown in FIGS. 1-5. A central portion of the strip 77 is removed to accommodate, the magnetic element 80 in the center of the lower edge of the door 73 for holding the same in the closed position even when subjected to wind gusts which would normally cause fluttering.

A front shield 82 (FIG. 8) is secured near the top and sides of the door 73 and extends outwardly and downwardly so that access to the duct 63 can only be gained through the outlet opening 85 defined by the shield thus prohibiting rain and snow from impairing the operation of the door 73 or gaining access to the duct 63. If desired, a screen can be secured across the opening 85 to ing 62 is running, sufiicient pressure is created in the duct 63 for moving the door 73 quickly to its fully opened position, as shown in the broken lines of FIG. 6, wherein it in no way obstructs or limits the outward flow of the exhaust gases. The upturned lip 87 on the lower edge of the door 73 maintains the magnetic element 80 in spaced relation with the shield 82 so that there is no tendency of the element 30 to hold the door in the open position.

Thus an improved ventilation hood'structure has been provided which does not depend for its operation on a spring or other biasing means which limit the extent that the door will open for any given pressure differential. On the other hand, the lightweight shutter door is flutterproof and airtight, although responsive to the exhaust gas pressure which quickly moves it to a fully open position. Each of the ventilation hoods provides a cover or shield for protecting the shutter door and the outlet duct from the elements while permitting obstruction free movement thereof. Furthermore, both embodiments of this invention are simple in design for maximum dependability and long life, as well as for inexpensive manufacture thereof.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is: v

A flutter-proof ventilation hood assembly comprising, a housing having an air passage therethrough, a mounting plate on said housing adapted to secure said housing in alignment with an aperture in a building structure, a metal frame secured in said housing and at least partially defining an outlet opening from said passage, a nonmagnetic metallic air flow operated door pivotally mounted on said frame for movement between a closed position wherein said door cooperates with said frame to close said opening and an open position wherein air will flow from the aperture through said opening, a soft resilient seal of polyurethane foam secured to all four sides of said frame between said frame and the periphery of said door for suppressing the noise of contact therebetween and for sealing against air flow between said frame and said door when said door is in said closed position, said frame and door being disposed in said housing so that gravity urges said door to said closed position, said seal having a centrally disposed open section on the edge of said door opposite the pivot support for said door, a short strip of magnetized rubber-like material secured to said open space on the lower edge of said door in alignment with said open section for cooperation with said metal frame to hold said door in said closed position until a predetermined pressure differential moves said door to said open position, said short strip of magnetized material having a thickness slightly less than the corresponding thickness of said resilient foam seal so that when said strip of magnetized material contacts said frame said door compresses said seal to insure a substantially airtight seal therebetween, a shield extending from said housing above and on each side of said door for blocking the flow of rain and the like into said housing, and an upturned lip on said lower edge of said nonmagnetic door for contacting said shield when in said open position to maintain a preset distance between said magnetic element and said shield means.

References Cited by the Examiner UNITED STATES PATENTS WILLIAM F. ODEA, Primary Examiner.

JOHN F. OCONNOR, Examiner. 

